title: Diffusion-weighted imaging with acquisition of three b-values for response evaluation of neuroendocrine liver metastases undergoing selective internal radiotherapy.
abstract: OBJECTIVE
  To evaluate diffusion-weighted MRI with acquisition of three b-values and calculation of fractioned ADCs for response evaluation of neuroendocrine liver metastases undergoing selective internal radiotherapy (SIRT).
  
  
  METHODS
  Ten consecutive patients with neuroendocrine liver metastases underwent MRI before and following SIRT. Diffusion-weighted imaging included acquisition of the b-values 0, 50 and 800 s/mm(2) and calculation of ADC(50,800), ADC(0,50) and ADC(0,800) maps. According to therapy response, lesions were categorised into group A [≥20% reduction of the longest diameter (LD) in comparison to baseline MRI] and group B (<20% reduction of the LD).
  
  
  RESULTS
  Twelve out of 31 metastases were categorised as group A and 19 out of 31 metastases were categorised as group B. Pretherapeutic values of ADC(0,800) and ADC(50,800) did not differ significantly between the two groups; however, ADC(0,50) was 32% lower in group A (P = 0.049). ADC(0,800) and ADC(50,800) increased significantly after therapy in both groups, however, group differences were not statistically significant. Conversely, the increase in ADC(0,50) was about a factor of 7 larger in group A than in group B (P = 0.023).
  
  
  CONCLUSIONS
  Our study showed that the ADC(0,50) is a promising biomarker for response assessment of neuroendocrine liver metastases following SIRT.
  
  
  CONCLUSIONS
  • Diffusion-weighted MRI offers new information about neuroendocrine hepatic metastases. • Evaluation of perfusion and diffusion components requires fractioned apparent diffusion coefficients (ADCs). • Perfusion effects represented by ADC (0.50) can be observed in neuroendocrine metastases. • Pretherapeutic ADC (0.50) was significantly lower in metastases with a response ≥20%. • Such biomarkers may help evaluate liver metastases in patients undergoing therapy.
authors.affiliation: Department of Radiology, University of Bonn, Sigmund-Freud-Str. 25, 53127, Bonn, Germany, guido.kukuk@ukb.uni-bonn.de.
authors.forename: Guido M
authors.initials: GM
authors.lastname: Kukuk
authors.forename: Petra
authors.initials: P
authors.lastname: Mürtz
authors.forename: Frank
authors.initials: F
authors.lastname: Träber
authors.forename: Carsten
authors.initials: C
authors.lastname: Meyer
authors.forename: Jan
authors.initials: J
authors.lastname: Ullrich
authors.forename: Jürgen
authors.initials: J
authors.lastname: Gieseke
authors.forename: Hojjat
authors.initials: H
authors.lastname: Ahmadzadehfar
authors.forename: Samer
authors.initials: S
authors.lastname: Ezziddin
authors.forename: Hans H
authors.initials: HH
authors.lastname: Schild
authors.forename: Winfried A
authors.initials: WA
authors.lastname: Willinek
mesh_terms: D000368:Aged; D001918:Brachytherapy / Q000379:methods*; D003937:Diagnosis, Differential; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D005770:Gastrointestinal Neoplasms / Q000473:pathology* / Q000532:radiotherapy*; D006801:Humans; D008113:Liver Neoplasms / Q000175:diagnosis* / Q000532:radiotherapy* / Q000556:secondary; D008297:Male; D008863:Microspheres; D008875:Middle Aged; D018358:Neuroendocrine Tumors / Q000175:diagnosis* / Q000532:radiotherapy* / Q000556:secondary; D012189:Retrospective Studies